Spring MVC整合FreeMarker

什么是Freemarker?
    FreeMarker是一个用Java语言编写的模板引擎，它基于模板来生成文本输出。FreeMarker与Web容器无关，即在Web运行时，它并不知道Servlet或HTTP。它不仅可以用作表现层的实现技术，而且还可以用于生成XML，JSP或Java 等。
    目前企业中:主要用Freemarker做静态页面或是页面展示

一.工程结构

二.web.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">  

     <display-name>SpringMVC</display-name>  

     <context-param>
         <param-name>contextConfigLocation</param-name>
         <param-value>/WEB-INF/springMVC-servlet.xml</param-value>
     </context-param>  

     <listener>
         <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
     </listener>  

     <filter>
         <filter-name>encodingFilter</filter-name>
         <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
         <init-param>
             <param-name>encoding</param-name>
             <param-value>UTF-8</param-value>
         </init-param>
         <init-param>
             <param-name>forceEncoding</param-name>
             <param-value>true</param-value>
         </init-param>
     </filter>
     <filter-mapping>
         <filter-name>encodingFilter</filter-name>
         <url-pattern>/*</url-pattern>
     </filter-mapping>  

     <servlet>
         <servlet-name>springMVC</servlet-name>
         <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
         <load-on-startup>1</load-on-startup>
     </servlet>
     <servlet-mapping>
         <servlet-name>springMVC</servlet-name>
         <url-pattern>/</url-pattern>
     </servlet-mapping>
 </web-app>   

三.springMVC-servlet.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
     xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
     xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://www.springframework.org/schema/beans
                     http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
                     http://www.springframework.org/schema/context
                     http://www.springframework.org/schema/context/spring-context-3.0.xsd
                     http://www.springframework.org/schema/mvc
                     http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
                     ">
     <!-- 自动扫描包 -->
     <context:component-scan base-package="com.bijian.study.controller"></context:component-scan>     

     <!-- 默认注解映射支持 -->
     <mvc:annotation-driven></mvc:annotation-driven>  

     <!--JSP视图解析器-->
     <bean id="viewResolverJsp" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
         <property name="prefix" value="/WEB-INF/views/"/>
         <property name="suffix" value=".jsp"/>
         <property name="viewClass" value="org.springframework.web.servlet.view.InternalResourceView"/>
         <property name="order" value="1"/>
     </bean>  

     <!-- 配置freeMarker视图解析器 -->
     <bean id="viewResolverFtl" class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">
         <property name="viewClass" value="org.springframework.web.servlet.view.freemarker.FreeMarkerView"/>
         <property name="contentType" value="text/html; charset=UTF-8"/>
         <property name="exposeRequestAttributes" value="true" />
         <property name="exposeSessionAttributes" value="true" />
         <property name="exposeSpringMacroHelpers" value="true" />
         <property name="cache" value="true" />
         <property name="suffix" value=".ftl" />
         <property name="order" value="0"/>
     </bean>  

     <!-- 配置freeMarker的模板路径 -->
     <bean id="freemarkerConfig" class="org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer">
         <property name="templateLoaderPath" value="/WEB-INF/ftl/"/>
         <property name="freemarkerVariables">
             <map>
                 <entry key="xml_escape" value-ref="fmXmlEscape" />
             </map>
         </property>
         <property name="defaultEncoding" value="UTF-8"/>
         <property name="freemarkerSettings">
             <props>
                 <prop key="template_update_delay">3600</prop>
                 <prop key="locale">zh_CN</prop>
                 <prop key="datetime_format">yyyy-MM-dd HH:mm:ss</prop>
                 <prop key="date_format">yyyy-MM-dd</prop>
                 <prop key="number_format">#.##</prop>
             </props>
         </property>
     </bean>  

     <bean id="fmXmlEscape" class="freemarker.template.utility.XmlEscape"/>
 </beans>  

在JSP和Freemarker的配置项中都有一个order property，上面例子是把freemarker的order设置为0，jsp为1，意思是找view时，先找ftl文件，再找jsp文件做为视图。这样Freemarker视图解析器就能与JSP视图解析器并存。

四.FreeMarkerController.java

 package com.bijian.study.controller;  

 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;  

 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;  

 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.servlet.ModelAndView;  

 import com.alibaba.fastjson.JSON;
 import com.bijian.study.utils.JsonUtil;
 import com.bijian.study.vo.User;  

 @Controller
 public class FreeMarkerController {     

     @RequestMapping("/get/usersInfo")
     public ModelAndView Add(HttpServletRequest request, HttpServletResponse response) {     

         User user = new User();
         user.setUsername("zhangsan");
         user.setPassword("1234");  

         User user2 = new User();
         user2.setUsername("lisi");
         user2.setPassword("123");   

         List<User> users = new ArrayList<User>();
         users.add(user);
         users.add(user2);
         return new ModelAndView("usersInfo", "users", users);
     }  

     @RequestMapping("/get/allUsers")
     public ModelAndView test(HttpServletRequest request, HttpServletResponse response) {  

         List<User> users = new ArrayList<User>();
         User u1 = new User();
         u1.setUsername("王五");
         u1.setPassword("123");
         users.add(u1);  

         User u2 = new User();
         u2.setUsername("张三");
         u2.setPassword("2345");
         users.add(u2);  

         User u3 = new User();
         u3.setPassword("fgh");
         u3.setUsername("李四");
         users.add(u3);     

         Map<String, Object> rootMap = new HashMap<String, Object>();
         rootMap.put("userList", users);
         Map<String, String> product = new HashMap<String, String>();
         rootMap.put("lastProduct", product);
         product.put("url", "http://www.baidu.com");
         product.put("name", "green hose");  

         String result = JSON.toJSONString(rootMap);  

         Map<String, Object> resultMap = new HashMap<String, Object>();
         resultMap = JsonUtil.getMapFromJson(result);  

         return new ModelAndView("allUsers", "resultMap", resultMap);
     }
 }  

五.JsonUtil.java

 package com.bijian.study.utils;  

 import java.util.Map;  

 import com.alibaba.fastjson.JSON;  

 public class JsonUtil {  

     public static Map<String, Object> getMapFromJson(String jsonString) {
         if (checkStringIsEmpty(jsonString)) {
             return null;
         }
         return JSON.parseObject(jsonString);
     }  

     /**
      * 检查字符串是否为空
      * @param str
      * @return
      */
     private static boolean checkStringIsEmpty(String str) {
         if (str == null || str.trim().equals("") || str.equalsIgnoreCase("null")) {
             return true;
         }
         return false;
     }
 }  

 六.User.java

 ackage com.bijian.study.vo;  

 public class User {  

     private String username;
     private String password;  

     public String getUsername() {
         return username;
     }  

     public void setUsername(String username) {
         this.username = username;
     }  

     public String getPassword() {
         return password;
     }  

     public void setPassword(String password) {
         this.password = password;
     }
 }  

七.usersInfo.ftl

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 <html>
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <title>usersInfo</title>
 </head>
 <body>
 <#list users as user>
     <div>
         username : ${user.username},
         password : ${user.password}
     </div>
 </#list>
 </body>
 </html>  

八.allUsers.ftl

 <html>
  <head>
    <title>allUsers</title>
  </head>
  <body>
    <#list resultMap.userList as user>
        Welcome ${user.username}!&nbsp;&nbsp;id:${user.password}<br/>
    </#list>
    <p>Our latest product:
     <a href="${resultMap.lastProduct.url}">${resultMap.lastProduct.name}  </a>!
   </body>
 </html>  

九.运行效果

再输入http://localhost:8088/SpringMVC/greeting?name=zhangshan，JSP视图解析器运行依然正常。

至此,就结束完成整合了!